Jet propelled watercraft

1. Field of the Invention

The present invention relates to a jet propelled watercraft.

2. Description of the Related Art

U.S. Pat. No. 8,177,594 discloses a watercraft that includes an engine, a jet pump driven by the engine, a reverse gate, a shift actuator (reverse gate actuator), and an ECU (electronic controller). The shift actuator moves the reverse gate to a forward drive position, a neutral position, and a reverse drive position. The ECU controls the engine and the shift actuator.

The inventors of preferred embodiments of the present invention described and claimed in the present application conducted an extensive study and research regarding a jet propelled watercraft, such as the one described above, and in doing so, discovered and first recognized new unique challenges and previously unrecognized possibilities for improvements as described in greater detail below.

With the watercraft according to U.S. Pat. No. 8,177,594, when the engine stops, the ECU controls the shift actuator to move the reverse gate to the neutral position. However, the neutral position is a position between the forward drive position and the reverse drive position and it is difficult to keep the position of the reverse gate by a stopper, etc.

If a reverse gate operator arranged to operate the reverse gate is mechanically coupled to the reverse gate, it is possible to fix the reverse gate at the neutral position by friction (operation resistance) of the reverse gate operator. However, in the watercraft according to U.S. Pat. No. 8,177,594, the reverse gate operator is not mechanically coupled to the reverse gate. With this arrangement, at the neutral position, the position of the reverse gate is kept only by engagement of gears interposed between the shift actuator and the reverse gate. Therefore, when the reverse gate is moved to the neutral position when the engine is stopped, the reverse gate becomes unstable after the engine is stopped.

In order to overcome the previously unrecognized and unsolved challenges described above, a preferred embodiment according to a first aspect of the present invention provides a jet propelled watercraft including a body, a prime mover, a jet pump driven by the prime mover and jetting water from a jet port, a reverse gate changing a direction of the jet flow jetted from the jet pump, a shift actuator capable of moving a position of the reverse gate to a plurality of shift positions including a forward drive position, at which the direction of the jet flow is toward the rear of the body, a reverse drive position, at which the direction of the jet flow is toward the front of the body, and an intermediate position in between these positions, and a controller configured or programmed to execute a stoppage shift control of controlling the shift actuator to move the reverse gate to the forward drive position when stoppage of the prime mover is detected.

With this arrangement, when the prime mover stops, the reverse gate is moved to the forward drive position. The reverse gate is thus kept at the forward drive position after prime mover stoppage and the reverse gate is thus stabilized after prime mover stoppage.

In many cases, a jet propelled watercraft is stored on land. Frequently before storing the jet propelled watercraft on land, the jet pump is washed with water on land. In water-washing the jet pump, the reverse gate will be an obstacle if the reverse gate is at the neutral position. With the watercraft according to U.S. Pat. No. 8,177,594, with which the reverse gate is moved to the neutral position when the engine is stopped, the engine must be started to move the reverse gate to the forward drive position in order to perform water-washing of the jet pump. When the engine is thus started on land, cooling water is not supplied to the engine and the engine may overheat.

With a preferred embodiment of the present invention, the reverse gate is kept at the forward drive position after prime mover stoppage and the need to start the prime mover to move the reverse gate to the forward drive position in order to water-wash the jet pump is thus eliminated. A jet propelled watercraft that is easy in maintenance is thus provided.

A jet propelled watercraft according to a preferred embodiment of the present invention further includes a stopper, against which the reverse gate is pressed at the forward drive position. With this arrangement, the reverse gate is put in a state of being pressed against the stopper after prime mover stoppage. The reverse gate is thereby stabilized after prime mover stoppage.

In a preferred embodiment of the present invention, the controller is configured or programmed to execute the stoppage shift control after elapse of a predetermined time from the point at which the stoppage of the prime mover is detected.

In order to prevent the jet propelled watercraft from being driven forward or being driven in reverse immediately after prime mover startup, it may be considered to control the shift actuator to move the reverse gate to the intermediate position when the prime mover is started. If in this case, the stoppage shift control is executed immediately when the stoppage of the prime mover is detected, there is a possibility of performing a wasteful actuation of repeatedly switching the shift position of the reverse gate when the prime mover is restarted immediately after prime mover stoppage. For example, if the prime mover is stopped when the reverse gate is at a position other than the forward drive position, the shift position of the reverse gate is switched from the intermediate position or the reverse drive position to the forward drive position by the stoppage shift control. If the prime mover is restarted immediately thereafter, the shift position of the reverse gate is switched from the forward drive position to the intermediate position.

Therefore, with the present preferred embodiment, the stoppage shift control is executed after the elapse of the predetermined time from the point at which the stoppage of the prime mover is detected. A wasteful shift position switching actuation, such as that described above, is thus avoided when the prime mover is restarted immediately after prime mover stoppage.

In a preferred embodiment of the present invention, the jet propelled watercraft further includes a shift position command signal output outputting a shift position command signal that commands the shift position of the reverse gate and the controller is configured or programmed to further execute an ordinary shift control of controlling the shift actuator in accordance with the shift position command signal. With this arrangement, the shift position of the reverse gate is able to be switched in accordance with the shift position command signal output from the shift position command signal output.

In a preferred embodiment of the present invention, the controller is configured or programmed to control the shift actuator so that the reverse gate moves at a first movement speed under the ordinary shift control and so that the reverse gate moves at a second movement speed, slower than the first movement speed, under the stoppage shift control.

With this arrangement, the movement speed of the reverse gate under the stoppage shift control is made slower than the movement speed of the reverse gate under the ordinary shift control. The reason for this is that the stoppage shift control is not performed intentionally by an operator.

In a preferred embodiment of the present invention, the controller is configured or programmed to determine whether or not an obstacle that obstructs the movement of the reverse gate is present when executing the stoppage shift control and control the shift actuator to move the reverse gate to the intermediate position when it is determined that the obstacle is present.

With this arrangement, if an obstacle that obstructs the movement of the reverse gate is present when executing the stoppage shift control, the reverse gate is moved to the intermediate position. Jamming of the obstacle is thus avoided or the obstacle is thus released.

In a preferred embodiment of the present invention, the controller is configured or programmed to judge whether or not the obstacle is present based on a movement amount of the reverse gate per unit time. The presence or non-presence of the obstacle is thus judged accurately based on a state of movement of the reverse gate.

In a preferred embodiment of the present invention, the shift actuator is an electric shift actuator and the controller is configured or programmed to judge whether or not the obstacle is present based on an electric current flowing through the electric shift actuator. The electric current flowing through the electric shift actuator corresponds to a load applied thereto. Therefore, when the load on the electric shift actuator increases due to an obstacle, it is judged that the obstacle is present.

In a preferred embodiment of the present invention, the controller is configured or programmed to control the shift actuator to move the reverse gate to the intermediate position when starting up the prime mover. With this arrangement, the jet propelled watercraft is prevented from being driven forward or in reverse immediately after the prime mover is started up.

A preferred embodiment according to a second aspect of the present invention provides a jet propelled watercraft including a body, a prime mover, a jet pump driven by the prime mover and jetting water from a jet port, a reverse gate changing a direction of the jet flow jetted from the jet pump, a shift actuator capable of moving a position of the reverse gate to a plurality of shift positions including a forward drive position, at which the direction of the jet flow is toward the rear of the body, a reverse drive position, at which the direction of the jet flow is toward the front of the body, and an intermediate position in between these positions, and a controller configured or programmed to execute a stoppage shift control of controlling the shift actuator to move the reverse gate to the reverse drive position when stoppage of the prime mover is detected.

With this arrangement, when the prime mover stops, the reverse gate is moved to the reverse drive position. The reverse gate is thus kept at the reverse drive position after prime mover stoppage and the reverse gate is thus stabilized after prime mover stoppage.

The jet propelled watercraft according to a preferred embodiment of the present invention further includes a stopper, against which the reverse gate is pressed at the reverse drive position. With this arrangement, the reverse gate is put in a state of being pressed against the stopper after prime mover stoppage. The reverse gate is thus stabilized after prime mover stoppage.

In a preferred embodiment of the present invention, the controller is configured or programmed to execute the stoppage shift control after elapse of a predetermined time from the point at which the stoppage of the prime mover is detected.

In order to prevent the jet propelled watercraft from being driven forward or being driven in reverse immediately after prime mover startup, it may be considered to control the shift actuator to move the reverse gate to the intermediate position when the prime mover is started. If in this case, the stoppage shift control is executed immediately when the stoppage of the prime mover is detected, there is a possibility of performing a wasteful actuation of repeatedly switching the shift position of the reverse gate when the prime mover is restarted immediately after prime mover stoppage. For example, if the prime mover is stopped when the reverse gate is at a position other than the reverse drive position, the shift position of the reverse gate is switched from the intermediate position or the forward drive position to the reverse drive position by the stoppage shift control. If the prime mover is restarted immediately thereafter, the shift position of the reverse gate is switched from the reverse drive position to the intermediate position.

With the present preferred embodiment, the stoppage shift control is executed after the elapse of the predetermined time from the point at which the stoppage of the prime mover is detected and therefore a wasteful shift position switching actuation, such as that described above, is thus avoided when the prime mover is restarted immediately after prime mover stoppage.

In a preferred embodiment of the present invention, the jet propelled watercraft further includes a shift position command signal output outputting a shift position command signal that commands the shift position of the reverse gate and the controller is configured or programmed to further execute an ordinary shift control of controlling the shift actuator in accordance with the shift position command signal.

With this arrangement, the shift position of the reverse gate is switched in accordance with the shift position command signal output from the shift position command signal output.

In a preferred embodiment of the present invention, the controller is configured or programmed to control the shift actuator so that the reverse gate moves at a first movement speed under the ordinary shift control and so that the reverse gate moves at a second movement speed, slower than the first movement speed, under the stoppage shift control.

With this arrangement, the movement speed of the reverse gate under the stoppage shift control is made slower than the movement speed of the reverse gate under the ordinary shift control. The reason for this is that the stoppage shift control is not performed intentionally by an operator.

In a preferred embodiment of the present invention, the controller is configured or programmed to determine whether or not an obstacle that obstructs the movement of the reverse gate is present when executing the stoppage shift control and control the shift actuator to move the reverse gate to the intermediate position when it is determined that the obstacle is present.

With this arrangement, if an obstacle that obstructs the movement of the reverse gate is present when executing the stoppage shift control, the reverse gate is moved to the intermediate position. Jamming of the obstacle is thus avoided or the obstacle is thus released.

In a preferred embodiment of the present invention, the controller is configured or programmed to judge whether or not the obstacle is present based on a movement amount of the reverse gate per unit time. The presence or non-presence of the obstacle is thus judged accurately based on a state of movement of the reverse gate.

In a preferred embodiment of the present invention, the shift actuator is an electric shift actuator and the controller is configured or programmed to judge whether or not the obstacle is present based on an electric current flowing through the electric shift actuator. The electric current flowing through the electric shift actuator corresponds to a load applied thereto. Therefore, when the load on the electric shift actuator increases due to an obstacle, it is judged that the obstacle is present.

In a preferred embodiment of the present invention, the controller is configured or programmed to control the shift actuator to move the reverse gate to the intermediate position when starting up the prime mover. With this arrangement, the jet propelled watercraft is prevented from being driven forward or in reverse immediately after the prime mover is started up.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

FIG. 1 is a schematic view of a jet propelled watercraft according to a preferred embodiment of the present invention.

FIG. 2 is a perspective view of the arrangement of a vicinity of a handle of the jet propelled watercraft.

FIG. 3 is an enlarged perspective view of the arrangement of a vicinity of a right grip of the handle.

FIG. 4 is a schematic side view of the jet propelled watercraft in a state where a reverse gate is at a reverse drive position.

FIG. 5 is a schematic plan view of the arrangement of FIG. 4 .

FIG. 6 is a schematic side view of the jet propelled watercraft in a state where the reverse gate is at a forward drive position.

FIG. 7 is a schematic side view of the jet propelled watercraft in a state where the reverse gate is at a neutral position.

FIG. 8 is a schematic view of rotation angle positions of a shift arm at a forward drive position, a neutral position, and a reverse drive position.

FIG. 9 is a block diagram for describing the electrical arrangement of the jet propelled watercraft.

FIG. 10A is a characteristics diagram of a setting example of a throttle opening degree with respect to an accelerator operation amount.

FIG. 10B is a characteristics diagram of another setting example of the throttle opening degree with respect to the accelerator operation amount.

FIG. 11 is a flowchart of a procedure of an example of an engine start control process executed by an ECU.

FIG. 12 is a flowchart of a procedure of an example of a shift control process executed by the ECU when the engine is stopped.

FIG. 13 is a flowchart of a procedure of another example of a shift control process executed by the ECU when the engine is stopped.

FIG. 14 is a flowchart of a procedure of an example of an error monitoring process performed by the ECU.

FIG. 15 is a flowchart of a procedure of another example of an error monitoring process performed by the ECU.

FIG. 1 is a schematic view of a jet propelled watercraft according to a preferred embodiment of the present invention. The jet propelled watercraft 1 is a small vessel used to travel on a body of water, such as a lake or sea, etc. The jet propelled watercraft 1 according to the present preferred embodiment is a personal watercraft (PWC), for example.

The jet propelled watercraft 1 includes a body 2 , an engine 3 as a prime mover disposed in an interior of the body 2 , and a jet propulsion device 4 mounted on a rear portion of the body 2 . The engine 3 and the jet propulsion device 4 constitute a propulsion generator that applies a propulsive force to the body 2 .

The body 2 includes a hull 5 that defines a watercraft bottom and a deck 6 disposed above the hull 5 . The engine 3 is disposed in a space defined between the hull 5 and the deck 6 . Further in the space is disposed a battery B 1 that supplies electric power to electrical equipment included in the jet propelled watercraft 1 . The engine 3 is disposed in front of the jet propulsion device 4 .

The engine 3 is an internal combustion engine that includes a crankshaft 3 a rotatable around a rotation axis extending in a front/rear direction. The engine 3 includes an engine speed sensor 25 configured to detect a rotational speed of the engine 3 . The jet propulsion device 4 is driven by the engine 3 . The jet propulsion device 4 jets water, sucked into a watercraft interior (into the interior of the body 2 ) from the watercraft bottom, to a watercraft exterior (exterior of the body 2 ) to generate the propulsive force to propel the jet propelled watercraft 1 forward or in reverse.

A seat 7 , on which an operator sits, is disposed on the deck 6 . The seat 7 is disposed above the engine 3 . The seat 7 is disposed at a center in a width direction of the jet propelled watercraft 1 . A handle 8 is disposed in front of the seat 7 . The handle 8 is an operating member operated by the operator to change a direction of the body 2 .

FIG. 2 is a perspective view of the arrangement of a vicinity of the handle 8 . A display 9 is disposed in front of the handle 8 . The handle 8 includes a right grip 11 and a left grip 12 . A first accelerator operator (accelerator operator) 13 is rotatably mounted on the right grip 11 . A second accelerator operator (reverse gate operator) 14 is rotatably mounted on the left grip 12 . On the handle 8 , an operation box 15 is mounted at an inner side of the right grip 11 . A start switch 16 to start the engine and a stop switch 17 to stop the engine are provided at an inner side of the left grip 12 of the handle 8 .

The first accelerator operator 13 is mainly operated to drive the jet propelled watercraft 1 forward. In the present preferred embodiment, the first accelerator operator 13 preferably is a lever type that includes an accelerator lever. An amount of operation of the first accelerator operator 13 (operation angle of the accelerator lever; hereinafter referred to as the “first accelerator operation amount Am 1 ”) is detected by a first accelerator position sensor 18 . The first accelerator position sensor 18 is, for example, a potentiometer. The first accelerator position sensor 18 is an example of an accelerator operation detector that detects an operation state of the first accelerator operator 13 .

The second accelerator operator 14 is mainly operated to drive the jet propelled watercraft 1 in reverse or to reduce a forward speed of the jet propelled watercraft 1 . In the present preferred embodiment, the second accelerator operator 14 preferably is a lever type that includes a reverse lever. An amount of operation of the second accelerator operator 14 (operation angle of the reverse lever; hereinafter referred to as the “second accelerator operation amount Am 2 ”) is detected by a second accelerator position sensor 19 . The second accelerator position sensor 19 is, for example, a potentiometer. The second accelerator position sensor 19 is an example of a reverse gate operation detector that detects an operation state of the second accelerator operator 14 .

FIG. 3 is an enlarged perspective view of the arrangement of a vicinity of the right grip of the handle. A low-speed travel mode switch 21 , a constant-speed travel mode switch 22 , an acceleration fine adjustment switch 23 , and a deceleration fine adjustment switch 24 are provided in the operation box 15 . The switches 21 to 24 are disposed in a region enabling operation with a right thumb of the operator in a state where he/she holds the right grip 11 with the right hand.

The jet propelled watercraft 1 is made to travel in any of a plurality of travel modes. The plurality of travel modes include an ordinary travel mode, a low-speed travel mode, and a constant-speed travel mode, for example. The ordinary travel mode is a travel mode (first mode) in which the jet propelled watercraft 1 travels at a speed that is in accordance with operations of the first accelerator operator 13 and the second accelerator operator 14 . The low-speed travel mode is a mode (second mode) in which the jet propelled watercraft 1 travels at a predetermined low speed. The constant-speed travel mode is a mode in which the jet propelled watercraft 1 travels at the speed at the point at which the constant-speed travel mode switch 22 is operated.

The low-speed travel mode switch 21 is a switch configured to set the travel mode to the low-speed travel mode and is an example of a mode switching signal output that outputs a mode switching signal to switch from the ordinary travel mode to the low-speed travel mode. The fine adjustment switches 23 and 24 are switches configured to finely adjust the speed of the jet propelled watercraft 1 in the low-speed travel mode. The constant-speed travel mode switch 22 is a switch configured to set the travel mode to the constant-speed travel mode.

As shown in FIG. 1 , the jet propulsion device 4 includes a jet pump 32 , by which water of the watercraft exterior that is sucked in from the watercraft bottom is jetted rearward, and a reverse gate 33 , which changes a direction of a jet flow jetted from the jet pump 32 .

The jet pump 32 includes an intake 41 through which the watercraft exterior water is sucked in, an outlet 42 from which the water sucked in from the intake 41 is jetted rearward, and a flow passage 43 guiding the water sucked into the intake 41 to the outlet 42 . The jet pump 32 further includes an impeller 44 (rotor vane) and a stator vane 45 that are disposed in the flow passage 43 , a driveshaft 46 coupled to the impeller 44 , a nozzle 47 defining the outlet 42 , and a deflector 48 inclining the direction of the jet flow, jetted rearward from the nozzle 47 , to the right and left.

The intake 41 is opened at the watercraft bottom and the outlet 42 is opened rearward further to the rear than the intake 41 . The driveshaft 46 extends in the front/rear direction. A front end portion of the driveshaft 46 is disposed inside the watercraft and a rear end portion of the driveshaft 46 is disposed in the flow passage 43 . The front end portion of the driveshaft 46 is coupled to the crankshaft 3 a of the engine 3 via a coupling 49 . The impeller 44 is coupled to the driveshaft 46 . The stator vane 45 is disposed rearward of the impeller 44 . The nozzle 47 is disposed rearward of the stator vane 45 . The impeller 44 is rotatable around a central axis of the driveshaft 46 with respect to the flow passage 43 . The stator vane 45 is fixed with respect to the flow passage 43 . The nozzle 47 is fixed to the body 2 .

The engine 3 drives the impeller 44 , together with the driveshaft 46 , around the central axis of the driveshaft 46 . When the impeller 44 is driven to rotate, water is sucked into the flow passage 43 from the intake 41 and the water sucked into the flow passage 43 is fed from the impeller 44 to the stator vane 45 . By the water fed by the impeller 44 passing through the stator vane 45 , torsion of water flow generated by rotation of the impeller 44 is reduced and the water flow is straightened. The flow-straightened water is thus fed from the stator vane 45 to the nozzle 47 . The nozzle 47 has a tubular form extending in the front/rear direction and the outlet 42 is formed by a rear end portion of the nozzle 47 . The water fed to the nozzle 47 is thus jetted rearward from the rear end portion of the nozzle 47 .

FIG. 4 is a schematic side view showing the arrangement of a vicinity of the nozzle 47 in enlarged manner. FIG. 5 is a schematic plan view of the arrangement of FIG. 4 . The deflector 48 is disposed rearward of the nozzle 47 . The deflector 48 is supported by the nozzle 47 in a manner enabling rotation in a right/left direction. The deflector 48 has a hollow tube shape. The outlet 42 of the nozzle 47 is disposed inside the deflector 48 . The deflector 48 defines a jet port 31 that is opened rearward. The jet port 31 is disposed rearward of the outlet 42 . The water that is jetted rearward from the nozzle 47 passes through an interior of the deflector 48 and is jetted from the jet port 31 . A jetting direction of the water is in accordance with a right/left direction angle of the deflector 48 .

The reverse gate 33 is supported by the nozzle 47 in a manner enabling rotation around an up/down rotation axis Ag extending in the right/left direction. For the sake of description, in the following, front, rear, up, and down with respect to the reverse gate 33 shall refer to front, rear, up, and down as defined in a state where the reverse gate 33 is at the position shown in FIG. 4 and FIG. 5 . The reverse gate 33 includes a rear wall 51 as an opening/closing portion that opens/closes the jet port 31 of the deflector 48 , a left side wall 52 extending frontward from a left side portion of the rear wall 51 , and a right side wall 53 extending frontward from a right side portion of the rear wall 51 . The left side wall 52 and the right side wall 53 have fan shapes spreading toward the rear in side view. A left opening 54 that is opened obliquely forward to the left is located near a rear end of the left side wall 52 . A right opening 55 that is opened obliquely forward to the right is located near a rear end of the right side wall 53 . The left opening 54 and the right opening 55 are right/left symmetrical to a vertical plane passing through a right/left center of the reverse gate 33 .

A pair of right and left support brackets 61 are mounted to the nozzle 47 . Front end portions of the respective side walls 52 and 53 of the reverse gate 33 are supported by the support brackets 61 via bolts 62 , for example. The bolts 62 are inserted through the side walls 52 and 53 of the reverse gate 33 and screwed to the support brackets 61 . The bolts 62 are respectively disposed along the up/down rotation axis Ag and at the right and left of the nozzle 47 . The reverse gate 33 is thus enabled to rotate around the up/down rotation axis Ag with respect to the nozzle 47 .

The front end portions of the respective side walls 52 and 53 include curved end surfaces 33 a including portions that are arcuate-shaped around the up/down rotation axis Ag. The front end portions of the respective side walls 52 and 53 further include first rectilinear end surfaces 33 b connected to upper ends of the curved end surfaces 33 a and extending substantially upward and second rectilinear end surfaces 33 c connected to lower ends of the curved end surfaces 33 a and extending substantially downward.

The reverse gate 33 is capable of moving to a reverse drive position shown in FIG. 4 and FIG. 5 , a forward drive position shown in FIG. 6 , and a neutral position shown in FIG. 7 by rotating around the up/down rotation axis Ag. The forward drive position is a position at which the jet port 31 is not covered at all by the rear wall 51 of the reverse gate 33 in a rear view viewed along the jetting direction of the water jetted from the jet port 31 of the deflector 48 . The reverse drive position is a position at which the entire jet port 31 of the deflector 48 is covered by the rear wall 51 of the reverse gate 33 in the rear view. The neutral position is a predetermined position between the forward drive position and the reverse drive position and is a position at which a portion of the jet port 31 of the deflector 48 is covered by the rear wall 51 of the reverse gate 33 in the rear view.

In the state where the reverse gate 33 is disposed at the forward drive position (see FIG. 6 ), the jet port 31 of the deflector 48 is not covered by the reverse gate 33 and therefore the water jetted rearward from the outlet 42 of the nozzle 47 thus passes through the interior of the deflector 48 and is jetted rearward from the jet port 31 . A thrust in a forward drive direction that drives the body 2 forward is thus generated.

In the state where the reverse gate 33 is disposed at the reverse drive position (see FIG. 4 ), the entire jet port 31 of the deflector 48 is covered by the reverse gate 33 . The water jetted rearward from the jet port 31 thus collides against an inner surface of the reverse gate 33 and is thereafter jetted obliquely forward to the left and obliquely forward to the right from the left opening 54 and the right opening 55 . The reverse gate 33 thus changes the direction of the water, jetted rearward from the jet port 31 , toward the front. A thrust in a reverse drive direction that drives the body 2 in reverse is thus generated.

When the reverse gate 33 is disposed at the neutral position (see FIG. 7 ), a portion of the jet port 31 of the deflector 48 is covered by the reverse gate 33 . Therefore, while a portion of the water jetted from the jet port 31 is jetted rearward, another portion of the water jetted from the jet port 31 is jetted obliquely forward to the left and obliquely forward to the right from the left opening 54 and the right opening 55 . A thrust in the forward drive direction and a thrust in the reverse drive direction are thus generated. The neutral position is set, for example, at a position at which the forward drive direction thrust and the reverse drive direction thrust are equal or substantially equal.

Each support bracket 61 is provided with a stopper 63 which the reverse gate 33 is pressed against at the forward drive position (see FIG. 6 ) and the reverse drive position (see FIG. 4 ). The stopper 63 has a rectangular or substantially rectangular plate shape that is long in the up/down direction in side view. An upper end surface of the stopper 63 is a first stopper surface 63 a and a rear end surface of the stopper is a second stopper surface 63 b.

As shown in FIG. 6 , when the reverse gate 33 is at the forward drive position, the first rectilinear end surfaces 33 b of the respective side walls 52 and 53 of the reverse gate 33 are pressed against the first stopper surfaces 63 a of the stoppers 63 . As shown in FIG. 4 and FIG. 5 , when the reverse gate 33 is at the reverse drive position, the second rectilinear end surfaces 33 c of the respective side walls 52 and 53 of the reverse gate 33 are pressed against the second stopper surfaces 63 b of the stoppers 63 . As shown in FIG. 7 , when the reverse gate 33 is at the neutral position, the reverse gate 33 is not pressed against the stoppers 63 .

The jet propelled watercraft 1 includes a deflector moving mechanism (not shown) that rotates the deflector 48 to the right or left in accordance with an operation amount (steering angle) of the handle 8 . The deflector moving mechanism mechanically couples the handle 8 and the deflector 48 . The deflector moving mechanism includes, for example, a push-pull cable that transmits an actuation of the handle 8 to the deflector 48 . The deflector moving mechanism may be an electrically driven moving mechanism that includes an electric motor, for example. A straight drive position of the handle 8 is associated with a straight drive position of the deflector 48 . When the handle 8 is operated, the deflector 48 is rotated to the left or to the right by the deflector moving mechanism. The jetting direction of the water from the jet port 31 is thus changed to the right or left.

The jet propelled watercraft 1 further includes a reverse gate moving mechanism 64 (see FIG. 1 , FIG. 4 , FIG. 6 , and FIG. 7 ) that rotates the reverse gate 33 up and down based on operation of the first accelerator operator 13 and the second accelerator operator 14 . In the present preferred embodiment, the reverse gate moving mechanism 64 includes a shift actuator 65 , a shift arm 66 rotated by the shift actuator 65 , and a link 67 coupling the shift arm 66 and the reverse gate 33 . In the present preferred embodiment, the shift actuator 65 preferably is an electric motor, for example.

The link 67 is pushed or pulled when the shift arm 66 is rotated by the shift actuator 65 . The reverse gate 33 is thus rotated around the up/down rotation axis Ag. A shift position of the reverse gate 33 (hereinafter referred to simply as the “shift position”) is detected by a shift position sensor 68 . The shift position sensor 68 is an example of a shift position detector or a shift state detector that detects the shift position or a shift state. In the present preferred embodiment, the shift position sensor 68 preferably is a potentiometer that detects a rotation angle (rotation amount) of the shift arm 66 from a reference position set in advance.

FIG. 8 is a schematic view of rotation angle positions of the shift arm 66 at the forward drive position, the neutral position, and the reverse drive position. In the present preferred embodiment, the reference position P of the shift arm 66 is a position at which the shift arm 66 is perpendicular or substantially perpendicular to a horizontal plane of the body 2 . A position F, at which the shift arm 66 is rotated in a counterclockwise direction by just a predetermined angle θ F from the reference position P, indicates the rotation angle position of the shift arm 66 corresponding to the forward drive position of the reverse gate 33 . A position R, at which the shift arm 66 is rotated in a clockwise direction by just a predetermined angle θ R from the reference position P, indicates the rotation angle position of the shift arm 66 corresponding to the reverse drive position of the reverse gate 33 . A position N, at which the shift arm 66 is rotated in the clockwise direction by just a predetermined angle θ N from the reference position P, indicates the rotation angle position of the shift arm 66 corresponding to the neutral position of the reverse gate 33 .

FIG. 9 is a block diagram for describing the electrical configuration of the jet propelled watercraft 1 . The engine 3 , the shift actuator 65 , the display 9 , etc., are controlled by an ECU 70 (electronic controller) the defines a controller. The engine 3 includes a starter motor 71 , an ignition coil 72 , an injector 73 , and a throttle actuator 74 .

Switches, including the start switch 16 , the stop switch 17 , the low-speed travel mode switch 21 , the constant-speed travel mode switch 22 , the acceleration fine adjustment switch 23 , and the deceleration fine adjustment switch 24 , are connected to the ECU 70 . Further, sensors, including the first accelerator position sensor 18 , the second accelerator position sensor 19 , the engine speed sensor 25 , and the shift position sensor 68 , are connected to the ECU 70 .

Further, the display 9 , and actuators, such as the starter motor 71 , the ignition coil 72 , the injector 73 , the throttle actuator 74 , the shift actuator 65 , etc., are connected to the ECU 70 . The starter motor 71 is configured to perform cranking of the engine 3 . The injector 73 is configured to inject fuel into an air intake path of the engine 3 . The throttle actuator 74 is configured to drive a throttle valve (not shown) of the engine 3 to adjust an amount of air supplied to the air intake path of the engine 3 . The ignition coil 72 is configured to raise a voltage applied to a spark plug (not shown).

The ECU 70 includes a microcomputer (not shown) and a storage device such as a memory 81 storing a program thereof, etc. The ECU 70 further includes drive circuits (not shown) of the starter motor 71 , the throttle actuator 74 , and the shift actuator 65 . Information expressing the angles θ F , θ R , and θ N shown in FIG. 8 are stored in the storage device 81 .

The ECU 70 calculates a first throttle opening degree Θ 1 corresponding to the first accelerator operation amount Am 1 detected by the first accelerator position sensor 18 . The ECU 70 further calculates a second throttle opening degree Θ 2 corresponding to the second accelerator operation amount Am 2 detected by the second accelerator position sensor 19 .

A straight line L 1 in FIG. 10A indicates a setting example of the first throttle opening degree Θ 1 with respect to the first accelerator operation amount Am 1 . A straight line L 2 in FIG. 10A indicates a setting example of the second throttle opening degree Θ 2 with respect to the second accelerator operation amount Am 2 . The first throttle opening degree Θ 1 is set so as to increase linearly as the first accelerator operation amount Am 1 increases. Similarly, the second throttle opening degree Θ 2 is set so as to increase linearly as the second accelerator operation amount Am 2 increases. However, with the present preferred embodiment, a rate of change of the second throttle opening degree Θ 2 with respect to the second accelerator operation amount Am 2 (slope of the straight line L 2 ) is smaller than a rate of change of the first throttle opening degree Θ 1 with respect to the first accelerator operation amount Am 1 (slope of the straight line L 1 ). Therefore, when the first accelerator operation amount Am 1 and the second accelerator operation amount Am 2 are of the same value, the second throttle opening degree Θ 2 is less than the first throttle opening degree Θ 1 .

In the ordinary travel mode, the ECU 70 performs an ordinary rotational speed control process and an ordinary shift control process. In the ordinary rotational speed control process, the ECU 70 controls the throttle actuator 74 in accordance with the first throttle opening degree Θ 1 and the second throttle opening degree Θ 2 to control the engine speed. Specifically, when the shift position is the forward drive position, the ECU 70 controls the throttle opening degree, for example, in accordance with a difference between the first throttle opening degree Θ 1 and the second throttle opening degree Θ 2 (hereinafter referred to as the “throttle opening degree difference (Θ 1 −Θ 2 )”). When the shift position is the reverse drive position or the neutral position, the ECU 70 controls the throttle opening degree, for example in accordance with the throttle opening degree Θ 2 .

The ECU 70 may perform the ordinary rotational speed control process by the same method as a rotational speed control method disclosed in United States Patent Application Publication No. 2013/0344754. The entire contents of US Patent Application Publication No. 2013/0344754 are incorporated herein by reference.

In the ordinary shift control process, the ECU 70 controls the shift actuator 65 in accordance with the first throttle opening degree Θ 1 , the second throttle opening degree Θ 2 , and the engine speed V detected by the engine speed sensor 25 to control the shift position.

When for example, in a case where the shift position is the forward drive position, the throttle opening degree difference (Θ 1 −Θ 2 ) is less than a predetermined value, the second accelerator operator 14 is operated, and the engine speed V is greater than a predetermined speed, the ECU 70 switches the shift position to the neutral position. Specifically, the ECU 70 sets a target shift position to the neutral position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the target shift position. The most recent target shift position is held in the storage 81 . The ECU 70 judges whether or not the reverse gate 33 has reached the target shift position. Specifically, the ECU 70 judges whether or not the rotation angle detected by the shift position sensor 68 has become equal to the angle, among the angles θ F , θ R , and θ N stored in the storage 81 , corresponding to the target shift position.

When for example, in a case where the shift position is the forward drive position, the throttle opening degree difference (Θ 1 −Θ 2 ) is less than the predetermined value, the second accelerator operator 14 is operated, and the engine speed V is not more than the predetermined speed, the ECU 70 switches the shift position to the reverse drive position. Specifically, the ECU 70 sets the target shift position to the reverse drive position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the target shift position.

When for example, in a case where the shift position is the neutral position, the engine speed V is less than the predetermined speed and the second accelerator operator 14 is operated, the ECU 70 switches the shift position to the reverse drive position. Specifically, the ECU 70 sets the target shift position to the reverse drive position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the target shift position.

When for example, in a case where the shift position is the neutral position, the engine speed V is less than the predetermined speed, the second accelerator operator 14 is not operated, and the first accelerator operator 13 is operated, the ECU 70 switches the shift position to the forward drive position. Specifically, the ECU 70 sets the target shift position to the forward drive position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the target shift position.

When for example, in a case where the shift position is the reverse drive position, the second accelerator operator 14 is not operated and the first accelerator operator 13 is operated, the ECU 70 switches the shift position to the forward drive position. Specifically, the ECU 70 sets the target shift position to the forward drive position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the target shift position.

When for example, in a case where the shift position is the reverse drive position, a state where the second accelerator operator 14 and the first accelerator operator 13 are not operated is sustained for not less than a predetermined time, the ECU 70 switches the shift position to the neutral position. Specifically, the ECU 70 sets the target shift position to the neutral position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the target shift position.

The reverse gate 33 is thus controlled in position in accordance with the operation of the second accelerator operator 14 . That is, the second accelerator operator 14 and the second accelerator position sensor 19 that detects the operation amount thereof constitute a shift switching signal output that outputs a shift switching signal or a shift position command signal output that outputs a shift position command signal.

The ECU 70 may perform the ordinary shift control process by the same method as a shift control method disclosed in United States Patent Application Publication No. 2013/0344754.

FIG. 11 is a flowchart of a procedure of an example of an engine start control process executed by the ECU 70 .

The ECU 70 determines whether or not the start switch 16 has been turned on in a state where the engine is stopped (step S 1 ). If the start switch 16 has not been turned on (step S 1 : NO), the ECU 70 returns to step S 1 .

If in step S 1 , it is determined that the start switch 16 has been turned on (step S 1 : YES), the ECU 70 determines whether or not the first accelerator operator 13 is being operated (step S 2 ). Specifically, the ECU 70 determines whether or not the first accelerator operation amount Am 1 detected by the first accelerator position sensor 18 is not less than a first threshold α 1 . The ECU 70 determines that the first accelerator operator 13 is being operated if the first accelerator operation amount Am 1 is not less than the first threshold α 1 , and determines that the first accelerator operator 13 is not being operated if the first accelerator operation amount Am 1 is less than the first threshold α 1 .

If it is determined that the first accelerator operator 13 is not being operated (step S 2 : NO), the ECU 70 determines whether or not the second accelerator operator 14 is being operated (step S 3 ). Specifically, the ECU 70 determines whether or not the second accelerator operation amount Am 2 detected by the second accelerator position sensor 19 is not less than a second threshold α 2 . The ECU 70 determines that the second accelerator operator 14 is being operated if the second accelerator operation amount Am 2 is not less than the second threshold α 2 , and determines that the second accelerator operator 14 is not being operated if the second accelerator operation amount Am 2 is less than the second threshold α 2 .

With the present preferred embodiment, the second threshold α 2 is set to a value greater than the first threshold α 1 as shown in FIG. 10A . Also with the present preferred embodiment, the first threshold α 1 and the second threshold α 2 are set so that a first throttle opening degree Θ 1 corresponding to the first threshold α 1 and a second throttle opening degree Θ 2 corresponding to the second threshold α 2 are of equal value (Θa). That is, the engine speed corresponding to the first threshold α 1 and the engine speed corresponding to the second threshold α 2 are equal or substantially equal to each other.

If it is determined that the second accelerator operator 14 is not being operated (step S 3 : NO), the ECU 70 performs an engine starting process (step S 4 ). Specifically, the ECU 70 drives the starter motor 71 , the ignition coil 72 , and the injector 73 and performs fuel supply control and ignition control to start the engine 3 . The ECU 70 then determines whether or not the engine 3 has been started (step S 5 ). Specifically, the ECU 70 determines the starting of the engine 3 based on whether or not the engine speed V detected by the engine speed sensor 25 is not less than a predetermined start determination threshold β 1 . That is, the ECU 70 determines that the engine 3 has been started if the engine speed V is not less than the start determination threshold β 1 and determines that the engine 3 has not been started if the engine speed V is less than the start determination threshold β 1 . If it is determined that the engine 3 has not been started (step S 5 : NO), the ECU 70 returns to step S 4 to perform the engine starting process.

If in step S 5 , it is determined that the engine 3 has been started (step S 5 : YES), the ECU 70 determines whether or not the shift position is the neutral position (step S 6 ). If the shift position is other than the neutral position (step S 6 : NO), the ECU 70 sets the target shift position to the neutral position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the neutral position (step S 7 ). The ECU 70 then ends the engine start control process and starts control in the ordinary travel mode.

If in step S 6 , it is determined that the shift position is the neutral position (step S 6 : YES), the ECU 70 ends the engine start control process and starts control in the ordinary travel mode.

If in step S 2 , it is determined that the first accelerator operator 13 is being operated (step S 2 : YES), the ECU 70 returns to step S 1 . The ECU 70 also returns to step S 1 if in step S 3 , it is determined that the second accelerator operator 14 is being operated (step S 3 : YES).

If it is determined that the first accelerator operator 13 is being operated in step S 2 or it is determined that the second accelerator operator 14 is being operated in step S 3 , the ECU 70 may return to step S 1 upon displaying an error on the display 9 .

With the start control process of FIG. 11 , even when the start switch 16 is turned on, the starting of the engine 3 is prohibited if it is determined that the first accelerator operator 13 is being operated (step S 2 ). Driving of the body 2 forward by the moving of the reverse gate 33 to the forward drive position immediately after the starting of the engine is thus prevented. Further, the rotational speed of the engine 3 immediately after the starting of the engine is suppressed to a low speed and application of a large propulsive force to the body 2 immediately after the starting of the engine is avoided.

With the start control process of FIG. 11 , it is determined that the first accelerator operator 13 is being operated when the first accelerator operation amount Am 1 is not less than the first threshold α 1 . Whether or not the first accelerator operator 13 is being operated is thus determined appropriately, and accordingly, engine start prohibition when the first accelerator operator 13 is being operated is performed appropriately.

With the present preferred embodiment, the first accelerator operator 13 includes the accelerator lever. The first accelerator operation amount Am 1 corresponds to the operation angle of the accelerator lever. The operation state of the accelerator lever is thus determined appropriately and start prohibition of the engine 3 during accelerator lever operation is performed appropriately. More specifically, the starting of the engine 3 is prohibited when the operation angle of the accelerator lever is not less than the predetermined threshold. The starting of the engine 3 is thus prohibited appropriately.

With the start control process of FIG. 11 , even when the start switch 16 is turned on, the starting of the engine 3 is prohibited if it is determined that the second accelerator operator 14 is being operated (step S 3 ). The driving of the body 2 in reverse by the moving of the reverse gate 33 to the reverse drive position immediately after engine start is thus prevented. Further, the rotational speed of the engine 3 is suppressed to be low immediately after engine start and application of a large propulsive force to the body 2 immediately after engine start is avoided.

With the start control process of FIG. 11 , it is determined that the second accelerator operator 14 is being operated when the second accelerator operation amount Am 2 is not less than the second threshold α 2 . Whether or not the second accelerator operator 14 is being operated is thus determined appropriately, and accordingly, engine start prohibition when the second accelerator operator 14 is being operated is able to be performed appropriately.

With the present preferred embodiment, the second accelerator operator 14 includes the reverse lever. The second accelerator operation amount Am 2 corresponds to the operation angle of the reverse lever. The operation state of the reverse lever is thus determined appropriately and start prohibition of the engine 3 during reverse lever operation is performed appropriately. More specifically, the starting of the engine 3 is prohibited when the operation angle of the reverse lever is not less than the predetermined threshold. The starting of the engine 3 is thus prohibited appropriately.

With the present preferred embodiment, the first throttle opening degree Θ 1 corresponding to the first threshold α 1 and the second throttle opening degree Θ 2 corresponding to the second threshold α 2 are equal or substantially equal. That is, the rotational speed of the engine 3 corresponding to the first threshold α 1 and the rotational speed of the engine 3 corresponding to the second threshold α 2 are equal. Operations of the first accelerator operator 13 and the second accelerator operator 14 are thus determined based on the rotational speed of the engine 3 . The operations of the first accelerator operator 13 and the second accelerator operator 14 is thus determined from a standpoint of the magnitude of the propulsive force generated when the engine 3 is started. The start prohibition of the engine 3 is thus controlled more appropriately.

With the start control process of FIG. 11 , if, immediately after engine start, the shift position is determined to be other than the neutral position, the reverse gate 33 is moved to the neutral position (steps S 6 and S 7 ). As shall be described below, with the present preferred embodiment, the reverse gate 33 is moved to the forward drive position or the reverse drive position when the engine 3 is stopped. It is thus determined that the first accelerator operator 13 and the second accelerator operator 14 are not being operated, and when the engine 3 is started, the reverse gate 33 is at the forward drive position or the reverse drive position. Therefore, by performing the start control process of FIG. 11 , the reverse gate 33 is moved to the neutral position immediately after engine start and the body 2 is thus suppressed from being driven forward or in reverse immediately after engine start.

Even if, due to some cause, the engine 3 is started in a state where at least one of either the first accelerator operator 13 or the second accelerator operator 14 is being operated, the body 2 is suppressed from being driven forward or in reverse immediately after engine start. For example, if the first or second accelerator position sensor 18 or 19 is malfunctioning, the determination of step S 2 or S 3 will not be performed correctly and the engine 3 may thus be started in a state where at least one of either the first or second accelerator operator 13 or 14 is being operated. Even in such a case, the reverse gate 33 is moved to the neutral position immediately after engine start and therefore the driving of the body 2 forward or in reverse immediately after engine start is avoided.

FIG. 12 is a flowchart of a procedure of an example of a shift control process executed by the ECU 70 when the engine is stopped.

The ECU 70 determines whether or not the engine 3 has stopped (step S 11 ). Specifically, the ECU 70 acquires the engine speed V detected by the engine speed sensor 25 and stores the acquired engine speed V in the storage or memory 81 . For example, the engine speed V that was acquired previously and the engine speed V acquired currently are stored in the storage or memory 81 . The ECU 70 determines that the engine 3 has stopped if a condition that the previously acquired engine speed V is not less than a predetermined stoppage determination threshold β 2 and the currently acquired engine speed V is less than the stoppage determination threshold β 2 is satisfied. If this condition is not met, the ECU 70 determines that the engine 3 is being driven or that the state in which the engine is stopped is sustained.

If in step S 11 , it is determined that the engine 3 is being driven or that the state in which the engine is stopped is sustained (step S 11 : NO), the ECU 70 returns to step S 11 . If in step S 11 , it is determined that the engine 3 has stopped (step S 11 : YES), the ECU 70 determines whether or not a predetermined time T 1 has elapsed since the engine 3 stopped (step S 12 ). The predetermined time T 1 may be set, for example, to about 0.5 seconds. If it is determined that the predetermined time T 1 has not elapsed since the engine 3 stopped (step S 12 : NO), the ECU 70 determines whether or not the engine 3 has been restarted (step S 13 ). Specifically, the ECU 70 determines whether or not the engine speed V detected by the engine speed sensor 25 has become not less than a predetermined restart determination threshold β 3 . The restart determination threshold β 3 is set to a value not less than the stoppage determination threshold β 2 . The ECU 70 judges that the engine 3 has been restarted if the engine speed V is not less than the restart determination threshold β 3 and judges that the engine 3 is in the stopped state if the engine speed V is less than the restart determination threshold β 3 .

If in step S 13 , it is determined that the engine 3 has been restarted (step S 13 : YES), the ECU 70 returns to step S 11 . If in step S 13 , it is determined that the engine 3 has not been restarted (step S 13 : NO), the ECU 70 returns to step S 12 . Therefore, when the predetermined time T 1 elapses without the engine 3 being restarted after it has been determined in step S 11 that the engine 3 has stopped, a positive judgment is made in step S 12 . If the positive judgment is made in step S 12 , the ECU 70 enters step S 14 .

In step S 14 , the ECU 70 determines whether or not the shift position is the forward drive position (step S 14 ). If it is determined that the shift position is other than the forward drive position (the neutral position or the reverse drive position) (step S 14 : NO), the ECU 70 sets the target shift position to the forward drive position and thereafter controls the shift actuator 65 to move the reverse gate 33 to the forward drive position (step S 15 ). In this process, the ECU 70 decreases an electric current supplied to the shift actuator 65 with respect to that supplied during ordinary shift control to make the movement speed of the reverse gate 33 slower than the movement speed of the reverse gate 33 during the ordinary shift control. The reason for this is that the movement of the reverse gate 33 to the forward drive position when the engine is stopped is not performed intentionally by the operator. Thereafter, the process performed by the ECU 70 returns to step S 11 .

If it is determined in step S 14 that the shift position is the forward drive position (step S 14 : YES), the ECU 70 returns to step S 11 .

In the process of FIG. 12 , when, after engine stoppage, the predetermined time T 1 elapses without restart of the engine 3 (YES in step S 12 ), it is determined whether or not the shift position is the forward drive position (step S 14 ). If the shift position is determined to be other than the forward drive position, the reverse gate 33 is moved to the forward drive position (step S 15 ). The reverse gate 33 is thus kept at the forward drive position after engine stoppage. As mentioned above, when the reverse gate 33 is at the forward drive position, the first rectilinear end surfaces 33 b of the respective side walls 52 and 53 of the reverse gate 33 are in a state of being pressed against the first stopper surfaces 63 a of the stoppers 63 (see FIG. 6 ). The reverse gate 33 is thus stabilized after engine stoppage.

In many cases, the jet propelled watercraft 1 is stored on land. Frequently before storing the jet propelled watercraft 1 on land, the jet pump 32 is washed with water on land. In water-washing the jet pump 32 , the reverse gate 33 will be an obstacle if the reverse gate 33 is at the neutral position. With the watercraft according to U.S. Pat. No. 8,177,594, with which the reverse gate is moved to the neutral position when the engine is stopped, the engine must be started to move the reverse gate to the forward drive position in order to perform water-washing of the jet pump. On the other hand, with the present preferred embodiment, the reverse gate 33 is kept at the forward drive position after engine stoppage. Therefore, there is no need to start the engine 3 to move the reverse gate 33 in order to water-wash the jet pump 32 . The jet propelled watercraft 1 that is easy in maintenance after use is thus provided.

With the process of FIG. 12 , when the engine 3 is stopped, step S 14 is not entered immediately but step S 14 is entered after the predetermined time T 1 elapses without the engine 3 being restarted (see steps S 12 and S 13 ). The reason for this shall now be described.

As described with the engine start control process of FIG. 11 , if when the engine 3 is started, the shift position is other than the neutral position, the reverse gate 33 is moved to the neutral position. Therefore, if the process of the ECU 70 enters step S 14 immediately when the engine 3 is stopped, the switching of the shift position may be performed repeatedly when the engine is restarted immediately after engine stoppage. For example, when the engine 3 is stopped with the reverse gate 33 being at a position other than the forward drive position, the shift position is switched from the neutral position or the reverse drive position to the forward drive position by the processes of steps S 14 and S 15 . If the engine is restarted immediately thereafter, the shift position is switched from the forward drive position to the neutral position. To avoid such wasteful switching of the shift position, in the present preferred embodiment, the process of the ECU 70 is made to enter step S 14 under the condition that the predetermined time T 1 elapses without the engine 3 being restarted after the engine 3 has stopped.

FIG. 13 is a flowchart of a procedure of another example of a shift control process executed by the ECU 70 when the engine is stopped. The processes of steps S 11 , S 12 , and S 13 of FIG. 13 are respectively the same as the processes of steps S 11 , S 12 , and S 13 of FIG. 12 and description thereof shall thus be omitted.

If in step S 12 , it is determined that the predetermined time T 1 has elapsed without the engine 3 being restarted after the engine 3 has stopped (step S 12 : YES), the ECU 70 determines whether or not the shift position is the reverse drive position (step S 14 A). If it is determined that the shift position is other than the reverse drive position (the neutral position or the forward drive position) (step S 14 A: NO), the ECU 70 controls the shift actuator 65 to move the reverse gate 33 to the reverse drive position (step S 15 A). In this process, the ECU 70 decreases the electric current supplied to the shift actuator 65 with respect to that supplied during ordinary shift control to make the movement speed of the reverse gate 33 slower than the movement speed of the reverse gate 33 during the ordinary shift control. Thereafter, the ECU 70 returns to step S 11 .

If it is determined in step S 14 A that the shift position is the reverse drive position (step S 14 A: YES), the ECU 70 returns to step S 11 .

By the process of FIG. 13 , the reverse gate 33 is kept at the reverse drive position after engine stoppage. As mentioned above, when the reverse gate 33 is at the reverse drive position, the second rectilinear end surfaces 33 c of the respective side walls 52 and 53 of the reverse gate 33 are in a state of being pressed against the second stopper surfaces 63 b of the stoppers 63 (see FIG. 4 ). The reverse gate 33 is thus stabilized after engine stoppage.

FIG. 14 is a flowchart for describing a procedure of an example of an error monitoring process. The ECU 70 may perform this error monitoring process when the reverse gate 33 is being moved to the forward drive position by the process of step S 15 of FIG. 12 or when the reverse gate 33 is being moved to the reverse drive position by the process of step S 15 A of FIG. 13 .

The ECU 70 determines whether or not an output value Vs of the shift position sensor 68 has changed within a predetermined time T 2 (step S 21 ). If it is determined that the output value Vs of the shift position sensor 68 has changed within the predetermined time T 2 (step S 21 : YES), the ECU 70 enters step S 22 . In step S 22 , the ECU 70 determines whether or not a change amount per unit time of the output value Vs of the shift position sensor 68 is not more than a predetermined time γ 1 . The change amount per unit time of the output value Vs of the shift position sensor 68 corresponds to a movement amount of the reverse gate 33 per unit time.

If it is determined that the amount of change per unit time of the output value Vs of the shift position sensor 68 is greater than the predetermined value γ 1 (step S 22 : NO), the ECU 70 enters step S 23 . In step S 23 , the ECU 70 determines, based on the output value Vs of the shift position sensor 68 , whether or not a rotation direction of the shift actuator 65 is the reverse of a rotation direction (commanded rotation direction) commanded by the ECU 70 . If the reverse gate 33 is being moved by the process of step S 15 of FIG. 12 , the commanded rotation direction is the rotation direction in which the reverse gate 33 is moved to the forward drive position. On the other hand, if the reverse gate 33 is being moved by the process of step S 15 A of FIG. 13 , the commanded rotation direction is the rotation direction in which the reverse gate 33 is moved to the reverse drive position.

If the rotation direction of the shift actuator 65 is the same direction as the commanded rotation direction (step S 23 : NO), the ECU 70 determines whether or not the movement of the reverse gate 33 has been completed (step S 24 ). If the movement of the reverse gate 33 has not been completed (step S 24 : NO), the ECU 70 returns to step S 21 .

If in step S 21 , it is determined that the output value Vs of the shift position sensor 68 did not change within the predetermined time T 2 (step S 21 : NO), the ECU 70 determines that an obstacle that obstructs the movement of the reverse gate 33 is present and enters step S 25 . Also, if in step S 22 , it is determined that the change amount per unit time of the output value Vs of the shift position sensor 68 is not more than the predetermined value γ 1 (step S 22 : YES), the ECU 70 determines that an obstacle that obstructs the movement of the reverse gate 33 is present and enters step S 25 . Also, if in step S 23 , it is determined that the rotation direction of the shift actuator 65 is the reverse of the commanded rotational direction (step S 23 : YES), the ECU 70 determines that an obstacle that obstructs the movement of the reverse gate 33 is present and enters step S 25 .

In step S 25 , the ECU 70 controls the shift actuator 65 to move the reverse gate 33 to the neutral position. Jamming of the obstacle is thus avoided or the obstacle is thus released. The ECU 70 then ends the process of the current error monitoring process cycle.

If in step S 24 , it is determined that the movement of the reverse gate 33 has been completed (step S 24 : YES), the ECU 70 ends the process of the current error monitoring process cycle.

By the error monitoring process shown in FIG. 14 , the presence or non-presence of an obstacle that obstructs the movement of the reverse gate 33 is monitored when the reverse gate 33 is being moved toward the forward drive position after engine stoppage by the process of step S 15 of FIG. 12 . If an obstacle is present, the reverse gate 33 is moved to the neutral position. Jamming of the obstacle is thus avoided and the obstacle is released to resolve the movement error.

Also, the presence or non-presence of an obstacle that obstructs the movement of the reverse gate 33 is monitored when the reverse gate 33 is being moved toward the reverse drive position after engine stoppage by the process of step S 15 A of FIG. 13 . If an obstacle is present, the reverse gate 33 is moved to the neutral position. Jamming of the obstacle is thus avoided and the obstacle is released to resolve the movement error.

By the error monitoring process shown in FIG. 14 , the presence or non-presence of an obstacle is judged accurately based on the movement state of the reverse gate 33 .

FIG. 15 is a flowchart of another example of an error monitoring process.

To perform this error monitoring process, the jet propelled watercraft 1 is provided with an electric current sensor 75 (indicated by alternate long and two short dashes lines in FIG. 9 ) configured to detect the electric current (hereinafter referred to as the “shift actuator current Is”) flowing through the shift actuator 65 . The electric current sensor 75 is connected to the ECU 70 .

The ECU 70 determines whether or not the shift actuator current Is detected by the current sensor 75 is not less than a predetermined value γ 2 (step S 31 ). If the shift actuator current Is is less than the predetermined value γ 2 (step S 31 : NO), the ECU 70 determines whether or not the movement of the reverse gate 33 has been completed (step S 32 ). If the movement of the reverse gate 33 has not been completed (step S 32 : NO), the ECU 70 returns to step S 31 .

If in step S 31 , it is determined that the shift actuator current Is is not less than the predetermined value γ 2 (step S 31 : YES), the ECU 70 determines that an obstacle that obstructs the movement of the reverse gate 33 is present and enters step S 33 . In step S 33 , the ECU 70 controls the shift actuator 65 to move the reverse gate 33 to the neutral position (step S 33 ). The ECU 70 then ends the process of the current error monitoring process cycle.

If in step S 32 , it is determined that the movement of the reverse gate 33 has been completed (step S 32 : YES), the ECU 70 ends the process of the current error monitoring process cycle.

The shift actuator current Is corresponds to a load applied to the shift actuator 65 . Therefore, by the error monitoring process shown in FIG. 15 , it is judged that an obstacle is present when the load on the shift actuator 65 increases due to the obstacle.

Although a preferred embodiment of the present invention has been described above, the present invention may be implemented in yet other preferred embodiments.

For example, with the preferred embodiment described above, in regard to the process of FIG. 11 , the first threshold α 1 and the second threshold α 2 preferably are set so that the first throttle opening degree Θ 1 corresponding to the first threshold α 1 and the second throttle opening degree Θ 2 corresponding to the second threshold α 2 are of equal value (Θa). However, the first threshold α 1 and the second threshold α 2 may be set so that the first throttle opening degree Θ 1 corresponding to the first threshold α 1 and the second throttle opening degree Θ 2 corresponding to the second threshold α 2 take on different values. In this case, the engine speed used to determine operation differs between the first accelerator operator 13 and the second accelerator operator 14 . The operations of the first accelerator operator 13 and the second accelerator operator 14 is thus determined from a standpoint of the respective magnitudes of the forward drive propulsive force and the reverse drive propulsive force generated when the engine 3 is started. The start prohibition of the engine 3 is thus controlled even more appropriately.

Also, with the preferred embodiments described above, the rate of change of the second throttle opening degree Θ 2 with respect to the second accelerator operation amount Am 2 preferably is set to be smaller than the rate of change of the first throttle opening degree Θ 1 with respect to the first accelerator operation amount Am 1 as shown in FIG. 10A . However, as shown in FIG. 10B , the rate of change of the second throttle opening degree Θ 2 with respect to the second accelerator operation amount Am 2 (slope of the straight line L 2 in FIG. 10B ) may be set to be equal to the rate of change of the first throttle opening degree Θ 1 with respect to the first accelerator operation amount Am 1 (slope of the straight line L 1 in FIG. 10B ). In this case, the first threshold α 1 and the second threshold α 2 may be set to the same value as shown in FIG. 10B . When the first threshold α 1 and the second threshold α 2 are set to the same value, the first throttle opening degree Θ 1 corresponding to the first threshold α 1 and the second throttle opening degree Θ 2 corresponding to the second threshold α 2 take on the same value (Θb).

With the preferred embodiments described above, in the ordinary travel mode, the ECU 70 performs the ordinary engine speed control process and the ordinary shift control process in accordance with the operation amount of the first accelerator operator 13 , the operation amount of the second accelerator operator (reverse gate operator) 14 , and the engine speed. However, in the ordinary travel mode, the ECU 70 may control the engine speed in accordance with the operation of the first accelerator operator 13 and perform shift control in accordance with the operation of the second accelerator operator 14 . That is, the second accelerator operator 14 may be used just to switch the shift position.

Although with the preferred embodiments described above, the second accelerator operator 14 preferably is a lever type, it may instead be of a grip type or may be a toggle switch or a button switch. Also, although with the preferred embodiments described above, the first accelerator operator 13 preferably is a lever type, it may instead be of a grip type.

If the second accelerator operator 14 is a switch, such as a toggle switch or button switch, etc., the second accelerator operator 14 constitutes a reverse gate operation detector that outputs a reverse gate position command signal in accordance with the operation of the second accelerator operator 14 . In this case, the ECU 70 determines, in step S 3 of FIG. 11 , that the second accelerator operator 14 is being operated when, for example, the reverse gate position command signal is being output by the second accelerator operator 14 . That is, whether or not the second accelerator operator 14 is being operated is determined based on whether or not the reverse gate position command signal is output. The starting of the engine 3 is thus prohibited under circumstances where there is a possibility for the reverse gate position to be changed in response to the position command signal. The starting of the engine 3 is thus prohibited appropriately.

With the preferred embodiments described above, the shift position of the reverse gate 33 preferably is detected by the shift position sensor 68 that detects the rotation angle of the shift arm 66 . However, the shift position may be detected by a plurality of limit switches.

Although with the preferred embodiments described above, the shift actuator 65 preferably is an electric motor, a hydraulic actuator may be used instead.

Although with the preferred embodiments described above, the case where the prime mover is the engine 3 was described, the prime mover may be an electric motor instead. In this case, the electric motor is started up as the prime mover in step S 4 of FIG. 11 . In step S 5 of FIG. 11 , it is judged whether or not the electric motor has been started up. In step S 11 of each of FIG. 12 and FIG. 13 , it is determined whether or not the electric motor has stopped. In step S 13 of each of FIG. 12 and FIG. 13 , it is determined whether or not the electric motor has been restarted.

Although with the preferred embodiments described above, the engine 3 , the shift actuator 65 , the display 9 , etc., preferably are controlled by a single ECU 70 , these may be controlled by a plurality of ECUs instead.

Also, although with the preferred embodiments described above, the case where the jet propelled watercraft preferably is a personal watercraft was described, the present invention may be applied to a jet propelled watercraft of another form, such as a jet boat, a sport boat, etc.

The present application corresponds to Japanese Patent Application No. 2014-162716 filed on Aug. 8, 2014 in the Japan Patent Office, and the entire disclosure of this application is incorporated herein by reference.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.